It's Been A While. New To Me Busa With Weird Throttle Issue.

[soundman]

Got back into the world of Hayabusas last week with the purchase of a very low mileage 2002 that had been sitting up for 4 years. Fixed the usual culprits of bad gas, rusted tank, clogged filter and fuel pump but got two issues that are baffling me

1) From closed throttle the throttle snaps off of the stop like its stuck. When the bike isn't running it doesn't to this but with the engine running it does it quite badly. I'm figuring that its vacuum trying to keep the butterflies closed but don't see any time of air bleed to allow air past them at idle.

2) The engine revs normally at a standstill in neutral but with the bike moving when I go to shift its like the throttle is sticking open and continues to rev. I've tried manually making sure that the throttle is closed but it still does it. If the bike is moving and I have the clutch pulled in the throttle blips normally.

The only mods to the bike are a plug in TRE module and dual Yosh exhausts.

 

[ROADTOAD1340]

Don't know if this will help , but what about throttle cable tension or the route of cables ? If all else fails , might be good idea to change your oil and filter and then take it to a reputable tuner / shop and get it dyno tuned / accessed . Good luck .

 

[jermzfree]

Check your intake boots for tears (connecting the throttle bodies to the engine) My dirtbike did something similar with a cracked boot causing an overly lean condition and surging rpm's Just a stab in the dart though.

 

[David Offor]

There should be adjustable throttle stops between the throttle bodies, theses are adjusted during throttle body synchronisation, to get optimal throttle response and smooth running, from what you’ve described, these are not adjusted correctly, I’d suggest a throttle body sync.
Other problem, try removing the throttle cables from the throttle body linkage and operate the throttle linkage by hand, this will eliminate possible binding throttle cables because of their routing, they will bind internally, over time, especially around the headstock route area.

 

[VIPER]

The key in this is when in gear. Remove the tre. Pull battery, clean all connections, reassemble. If this doesnt work, then sync tbs. I suspect the tre is causing yiou issues though. Also age of battery? I assume new as it sat for 4 years, but if not replace this as well.

 

[soundman]

Unplugged the TRE, Checked all battery connections and is behaving much better. Thanks for the input